Electric-lamp socket.



R. B. BENJAMIN ELECTRIC LAMP SOCKET.

APPLICATION FILED JAN.

Patented Nov. 24, 1914.

* support is subject to. vibration.

OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO, ILLINOIS, ASSIGNOR T BENJAMIN ELECTRICMFG. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRIC-LAMP SOCKET.

Specification of Letters Patent.

Patented Nov. 24, 1914.

Application filed January 31, 1912. Serial No. 674,537.

To all whom it may concern Be it known that I, REUBEN B. BENJAMIN, acitizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented new and useful Improvements inElectric-Lamp Sockets, of which the following is a full, clear, concise,and exact description, reference being had to the accompanying drawing,forming a part of this specification.

My invention pertains to electric lamp sockets such as are intended tobe used on shipboard, on cars, on busy streets, in factories, and inother places where the socket The vibrations to which the socket issubjected when used in such places as those noted above, have the effectof shaking the lamp loose in the socket; and the frequent necessity ofattending to sockets the lamps in which have thus become loose, has beenthe subject of much annoyance, especially in series systems, where morework than the mere tightening of the lamp must usually be done.

\Vith the above conditions in view, it is an object of my invention toprovide a socket which will be convenient in use and which will be ofsuch a nature that a lamp contained therein cannot be shaken loose byvibration.

It is a further object of my invention to produce a socket in which,while means are provided for preventing the lamp from being shakenloose, the lamp may be introduced and removed without the performance ofother operations than the ordinary ones of screwing the lamp in or out.

My invention is described in the following specification and shown inthe accompanying drawings, as applied to a lamp socket oi the typedisclosed in my co-pending application Serial No. 590,502, filedNovember 3, 1910; it may be embodied in other devices, however, withinthe scope of the appended claims.

In the drawings: Figure 1 is an elevational view, in section, showing alamp socket having my invention applied thereto; Fig. 2 is a plan of thelower base member; Fig. 3 is a sectional inverted plan, the sectionbeing taken on the line 3-3 of Fig. 1; and the parts being shown in theposition which they assume when a lamp is being withdrawn from thesocket; Fig. 4 is a similar view to Fig. 3, but showing the .position ofthe parts when a lamp is not present in the socket; and Fig. 5 is adetail perspective view of the threaded lamp-terminal-engaging contact.

Referring now to the drawings, 14; indicates a collar adapted to besecured to a conduit or the like and having external screw threads forreceiving a bracket 21, which clamps a casing-shade 12 in position uponthe collar, as shown. The bracket .21 carries a base consisting of anupper member 19 and a lower member 35, these parts being securedtogether and to the bracket by means of screws 37 which pass through themembers 19 and 35 and enter the bracket. The upper member 19 carries, onthe lower face thereof, a center contact 2i and a pair of bindingterminals 31 and the latter being therefore accessible when the lowermember is removed from the upper. The lower member 35 is formed with acentral aperture 38 in which is contained a threaded sleeve which formsthe outer lam 'i-terminal-engaging contact. The sleeve 30 is secured tothe member by means of a rivet 43 passing through a lug extend inglaterally from the sleeve, and is provided with a contact member -11which makes conneetion with the binding terminal 25 when the members 19and are secured together. The parts above described are connected andarranged in a like manner to similar parts in the device described in myco-pending application Serial No. 590,502.

in this embodiment of my invention, the threaded contact 39 is cut awayat its lower end throughout a portion of its circumference. the outbeing made along the line of the thread and leaving a lug 4-5 (Fig. 5),which acts as a guide for leading the threads oi. the lamp end intothose of the contact 39. A spiral spring 46 is wrapped upon the threadedcontact 39 in the thread groove thereof, the inner end 47 of the springbeing held against movement by being bent outward so as to enter arecess 48 in the wall oi the aperture 38. The spring 46 follows thethread groove of the contact 39 and emerges therefrom at the outercut-away portion of the contact. being carried, in' the embodiinentshown, beyond the contact for a distance of somewhat less than one turn,thus forming an extension 49. The extension as is of a reduced diameter,so that it will closely engage in the thread of the lamp end when a lampis screwed into the socket. The end 50 of the extension 49 is bentoutward as shown in Figs. 3 and 4 so as to enter a recess 51 formed inthe wall of the aperture 38, the parts being of such dimen sions thatthe end 50 of extension lies adjacent to, but normally does not touchthe wall of the recess (Fig. 4:).

The operation of the device is as follows: Vvhen a lamp is to beinserted into the socket, its end is pushed up against the outer end ofthe threaded contact 39, the extension 49 giving way and allowing thelug 45 to spring into the thread groove of the lamp end, whereby thelamp end is properly guided into the threaded contact 89. The lamp isthen screwed up into the contact 39, the effect of such movement be ingthat, owing to the frictional engagement of the extension 49 with thelamp end, the spring is unwound to a small extent, whereby the frictionbetween the extension 49 of the spring and the lamp end is diminished.The lamp may thus be inserted into the socket with very little effort.The extension 49, bearing upon the lamp end, effectually prevents thelamp from being shaken loose in the socket by the effect of anyvibrations to which the socket may be subjected. When, however, it isdesired to remove the lamp, this may be effected by unscrewing it in theordinary manner, the first effect of the unscrewing movement being that.the spring 46 is tightenedupon the threaded contact 89, and theextension 49 is tightened upon the lamp end. Tf the tightening of thespring end 49 upon the lamp end were permitted to continue, it would bedifficult, if not impossible, to unscrew the lamp from the contact 39.Tt will be noted, however, that, as the spring tightens, the end 50 ofthe extension L9 moves in a contraclockwise direction. After the springhas tightened to a certain extent, the end 50 engages against the stopformed by the wall of the recess 51, and is thereby prevented fromfurther movement. The extension 49 cannot thereafter contract about thelamp end and the lamp can therefore be unscrewed from the contact 39. Itwill be noted, therefore, that the stop formed by the wall of the recess51 has the effect of limit ing the contraction of the extension 49 aboutthe lamp end.

t will be seen that the above construction precludes any chance of thelamp becoming shaken loose in the socket; and does so while maintaininga simple and inexpensive construction. It is further to be noted thatthe lamp may be inserted into, and withdrawn from, the socket by theordinary operations of screwing in and screwing out, and without anyother operations being necessary.

nmaeea Having thus described my invention, what T claim as new anddesire to secure by Letters Patent, is:

1. Tu an electric lamp socket, the combination with a threaded lampreceiving shell, of a coiled spring wrapped about said shell and havinga portion of its coil of reduced diameter and extendinginto said shellto closely engage the lamp when the lamp is screwed into said. shell.

2. Tn an electric lamp socket for the reception of lamps having threadedends, the combination with a lamp receiving shell, of a coiled springwrapped about said shell and having one end thereof of reduced diameterand extending into said shell to closely engage the lamp when the lampis screwed into the shell, and a stop in a position to be engaged by theend of said spring after the lamp has been moved in adirection towithdraw the same from said device.

3. In an electric lamp socket forthe reception of lamps having threadedends, the combination with a threaded lamp-receiving shell, of a coilspring wrapped about said shell and having the outer end thereofextending beyond the outer end of said shell, such extended end of saidcoil spring being of a reduced diameter, whereby the extended end ofsaid coil spring is entered and closely engaged by thelamp end when alamp is screwed into said shell.

4. Tn an electric lamp socket for the reception of lamps having threadedends, the combination with a threaded lamp-receiving 10o shell having aguiding lug extending from the outer end thereof, of a coil springwrapped about said shell and having the outer end thereof extendingbeyond the outer end of said shell, such. extended end of said coilspring being of a reduced diameter, whereby the extended end of saidcoil spring is entered and closely engaged by the lamp end when a lampis screwed into said shell, and said lug guides said lamp end into saidshell.

5'. Tn an electric lamp socket for the reception of lamps havingthreaded ends, the combination with a threaded lamp-receiving shell, ofa coil spring wrapped about said shell and having the outer end thereofextending beyond the outer end of said shell, such extended end of saidcoil spring being of a reduced diameter, whereby the extended end ofsaid coil spring is entered and closely engaged by the lamp end when alamp is screwed into said shell, and means for engaging the outer' endof said coil ,spring after the lamp has been turned in a direction tounscrew it from said shell, whereby said engaging means limits thecontraction of the extended end of said coil spring about the lamp end.

6. Tn an electric lamp socket for the reception of lamps having threadedends, a

base having a chamber formed therein, a portion of said base beingformed, within said chamber, with a stop, a center lampterminal-engagingcontact disposed centrally with respect to said chamber, a threaded lampreceiving shell disposed in said chamber, a coil spring surrounding saidshell and having the outer part thereof extending beyond the outer endof said shell and having the end thereof adjacent to, but out of engagement with, said stop, such extended part of said coil spring being of areduced diameter, whereby the extended part of said coil spring isentered and closely engaged by the lam end when a lamp is screwed intosaid shel, and said stop limits the contraction of such extended partabout the lamp end during the removal of the lamp from the socket.

In witness whereof, I have hereunto subscribed my name in the presenceof two Witnesses.

REUBEN B. BENJAMIN. Witnesses:

MABEL REYNOLDS, C. E. KANE.

